There are many new features and layers, most notably the support of GPS, placefiles, a full automation system (FTP Uploading, etc.), and best of all, a completely new model data system that visualizes and animates NDFD, GFS, NAM, and RUC data. View screenshots here: http://weatherstudio.paulmarv.com/screenshots.html

There's also some information over at the GRLevelxStuff forum here (an old thread, mind you), and here.